When using a fuel which contains alcohol as a fuel, the higher the alcohol concentration in the fuel, the higher the octane value and the harder it becomes for knocking to occur. Therefore, the higher the alcohol concentration in the fuel, the higher the compression ratio can be made. Therefore, there is known an internal combustion engine which is provided with a variable compression ratio mechanism which can change a mechanical compression ratio and a variable valve timing mechanism which can control a closing timing of the intake valve, which uses a fuel which contains alcohol as a fuel, and which raises the actual compression ratio the higher the alcohol concentration in the fuel (see Patent Literature 1).